Multiple input fluid jet element for a fluidic circuit

ABSTRACT

A fluidic circuit device incorporates one or more multiple input fluidic jet elements arranged so that the jet axes of each of the jets is directed to a mixing region at an obtuse angle with respect to a baffle, and the ends of the nozzles of the multiple jet element define a line or plane that is at an acute angle with respect to the baffle. The nozzle system is disclosed in combination with a wall attachment device, as an arrangement to permit the series or parallel combining of signals, and in an arrangement having opposed elements.

United States Patent [191 Schwarz et al.

[ Dec. 25, 1973 MULTIPLE INPUT FLUID JET ELEMENT FOR A FLUIDIC CIRCUIT Inventors: Arnulf Schwarz; Gerhard Kiinig;

Manfred Pieloth; Dietmar Lang, all of Dresden, Germany Veb Reglerwerk Dresden, Dresden, Germany Filed: Mar. 31, 1972 Appl. No.: 240,038

Assignee:

Foreign Application Priority Data May 27, 1971 Germany WP F 15 c/ 155 394 US. Cl. 137/823, 137/837 Int. Cl. F15c 1/14 Field of Search 137/815, 823, 833, 137/842, 837

References Cited UNITED STATES PATENTS 9/1969 Simson 137/815 3.478,764 11/1969 Trask et al 137/8l.5 3,240,219 3/1966 Dexter et 211...... 137/8l.5 3,272,214 9/1966 Warren l37/8l.5 3,282,281 11/1966 Reader 137/81 5 3,326,463 6/1967 Reader 137/815 X 3,444,876 5/1969 Sielacki et a1. 137/815 3,603,335 9/1971 Lederman et a1 l37/8l.5

Primary ExaminerWilliam R. Cline Attorney-Nolte & Nolte [5 7] ABSTRACT A fluidic circuit device incorporates one or more multiple input fluidic jet elements arranged so that the jet axes of each of the jets is directed to a mixing region at an obtuse angle with respect to a baffle, and the ends of the nozzles of the multiple jet element define a line or plane that is at an acute angle with respect to the baffle. The nozzle system is disclosed in combination with a wall attachment device, as an arrangement to permit the series or parallel combining of signals, and in an arrangement having opposed elements.

10 Claims, 5 Drawing Figures MULTIPLE INPUT FLUID JET ELEMENT FOR A FLUIDIC CIRCUIT This invention relates to a multiple input fluidic jet element for use in processing signals in a fluidic circuit, and it is particularly directed to such an arrangement in which the input signals are substantially decoupled from each other.

Multiple input fluidic jet elements having several signal inputs terminating in jet form in parallel to a two or three dimensional arrangement in a common mixing device are known. Jet elements are also known in which two or more signal elements terminate in a preferential direction of flow and at predetermined angles in the form ofa branch in a common duct leading to the output of the element. In devices of this type, several signal inputs terminate unilaterally and obliquely in the direction of flow in the common duct. Such multiple input fluidic jet elements are not decoupled, and they therefore have substantial reaction on the respective inputs to which signals are not applied.

Arrangements for decoupling the signal inputs of multiple input fluidic jet elements are also known. The decoupling in most of this type of arrangement is effected by providing suitable ventilation into the surrounding atmosphere. Jet nozzle arrangements are furthermore known in which the nozzle directs their input jets from different directions and at different angles onto a common mixing device, with an atmospheric separating zone being arranged between the jets and the mixing device. In some arrangements of this type, the mixing devices are designed in a particular manner in order to avoid major power losses. In some such cases, the mixing device feeds an input of another identical multiple input jet element, so that the number of signal inputs is increased. In the past, devices of this type require nozzles that have geometrically complicated shapes, mixing devices and ducts in order to prevent large power losses, as well as adequate space for the advantageous design of such flow mechanical elements. Such arrangements also employ complicated technology in their manufacture in order to have the desired precision in reproduction.

Multiple input jet element arrangements are also known in which the signals from the individual mixing devices of several atmospherically decoupled inputs are combined in a given manner in a common duct, the duct serving as an output. In such arrangements, the decoupling of the signal inputs is only partly insured.

In still another arrangement, the multiple jet elements are arranged so that the signal inputs are directed parallel to, or at a given angle onto an auxiliary jet. The signal inputs are decoupled by the auxiliary jet, and the signals deflect the auxiliary jet when they are applied to the device. This arrangement requires the use of an extensive interaction'chamber, in which the deflection occurs. Equal deflection of the auxiliary jets from the inputs signals requires different amplitudes of the signals along the interaction region, since the optimum point of action for the deflection of the jet is locally constricted, even when the input jets are directed in their most favorable directions.

Previously employed jet elements of the type which combine the input jets in front of an atmospherically separated mixing region in one direction of action, are limited to the use of two symmetrically arranged inputs, or at the most three such inputs, in order to avoid too great a loss in power. The manufacture of such arrangements must meet very high standards, as a result of the acute angle convergence which is required, especially in miniaturized elements.

Multiple input jet elements of the type having inputs directed on a common auxiliary jet, in view of the arrangements of the elements, result in the production of reaction on oppositely disposed inputs.

It is therefore an object of this invention to provide a fluidic jet element for the processing of multiple input signals, in which the jets formed by the input signals are guided into a generally common direction of action, in which the number of signal inputs can be readily increased even in limited spaces, in which the input signals are substantial decoupled, in which the design of the arrangement is technologically not difficult, and in which the loss of power is low.

According to the invention, the above objects are achieved by providing a jet element having several nozzles which input signals are provided, one or more baffles, and one or more mixing regions from which the output signals are derived.

In the preferred arrangements according to the invention, the elements are designed so that the nozzles, baffles and mixing regions are substantially two dimensional, (i.e. having planar flow). The nozzles are arranged with respect to the baffle associated therewith, so that partial jets issuing from the nozzles form obtuse angles with the fluid flowing along the baffle in the direction of the respective mixing regions.

Each group of nozzles corresponds to a given baffle and a given mixing region. Several such groups can be combined to form a further modified jet element according to the invention.

Further, in accordance with the invention, the outlet planes, i.e. the planes or lines joining the nozzles in a group of nozzles, must intersect the plane of the respective baffle at an acute angle. The partial jets issue from their respective nozzle outlets within this acute angle.

In order to design the mixing regions, one or more walls are provided next to the baffle and spaced therefrom, preferably beyond the point on each baffle where the respective partial jets impinge, in order to define the region of the flow of the fluid. Such additional walls may be in the form of walls of other elements of the overall device, such as, for example, the end wall of a main jet nozzle in a wall attachment device. The mixing regions receive the fluid flowing along the baffle, and conduct it into adjoining fluidic elements of the same or different types.

The mixing regions, which receive the fluid flowing along the baffle, can, in accordance with the invention, be connected directly to the interaction region of a wall attachment device. In such arrangements the wall attachment device may be comprised of a nozzle system having one or throttles arranged in cascade with the main nozzle. If the input signals of the device have different potentials, similar nozzle systems may be employed for the input signals, i.e., with several throttles arranged in cascade in front of the respective nozzle and separated by intermediate chambers into which the input signals are separately introduced.

The multiple input jet element according to the invention has the further advantage that it is readily adaptable to parallel, series and counterconnection' processing of the input signals.

The contours of the elements of the nozzles, baffles, and mixing regions, according to the invention, are

preferably in the form of elevated webs or walls on a flat ground plate, the device being covered by a flat cover plate.

The arrangement of the present invention provides the advantage that the signal inputs of the multiple input jet elements are decoupled whether in parallel connection, series connection or counterconnection, and the signal inputs are thus substantially reaction free. The invention also permits the combining of signals having different spatial distributions, with relatively small loss in power in the common jet formed thereby, so that, for example, the jet formed thereby may be directed at the main jet of a wall attachment device at a favorable point in order to deflect the main jet. The arrangement according to the invention further provides the advantage that the number of signal inputs may be increased in a minimum of space, and such increase does not place any special demands on the manufacture as a result of the simple and easily manufactured geometric configurations. Since it is possible to employ simple technology in the arrangement, the arrangement may be advantageously manufactured, even with high reproduction precision, and in miniaturized form. The arrangement can be adapted to different input signals by simple geometric changes, which can be easily controlled in the manufacture of the arrangement, or by the use of specially prepared and designed input nozzle systems.

The invention will now be described more fully with respect to the accompanying drawings in which:

FIG. I is an illustration of a wall attachment fluidic device employing a multiple input jet arrangement according to the invention;

FIG. 2 is a cross sectional view of a portion of the arrangement of FIG. 1 taken along lines AA;

FIG. 3 is an illustration of a wall attachment device according to another embodiment of the invention employing an arrangement for applying input signals of different potential;

FIG. 4 illustrates a jet arrangement having several groups of nozzles forthe realization of complicated logical functions according to another embodiment of the invention; and

FIG. is an illustration of a further embodiment of the invention for the counter-connection of two jet elements.

Referring now to FIG. 1, therein is illustrated a wall attachment device having a multiple input jet arrangement according to the invention. The contours of the elements as shown in FIG. 1 represent elevated walls or straps 18 between which the fluid flows, employing a flat ground plate 19 and a flat cover plate as illustrated in FIG. 2. (In FIG. 1 the cover plate is omitted to enable clear illustration of the elements of the device.)

In the arrangement of FIG. 1 the multiple jet element is employed to realize the logical OR function, and consists of jet nozzles Ia to 1c. The input signals 2a to 2c are applied to the jet nozzles 1a to la respectively. The jet nozzles la to 1c are directed toward a baffle 3a by way of a mixing region 4a. The mixing region 4a is directly connected to the interaction region 5 of the wall attachment device, and is defined in part by the outer wall 35 of the end of jet nozzle system 6 of the device and in part by the baffle 30. The wall attachment device is also comprised of the nozzle system 6 having a main nozzle and cascade throttles 8 positioned between the source of supply fluid l5 and the main nozzle 7. The nozzle system 6 produces a high precision main jet, and is arranged so that the dimensions of the throttles are less than the distances between the throttles and the main nozzle 7. The main nozzle 7 may be in the form of a Borda mouthpiece. The arrangement of FIG. 1 further comprises angled walls 1 l and 12 necessary for the attachment and the alignment of the jet from the main nozzle, as well as mixing nozzles 9 and 10 for the signal outputs l3 and 14. The baffle 3a may be an extension of the angle wall 12 as illustrated in FIG. 1.

In the arrangement of FIG. I, the angle walls 11 and 12 are intentionally asymmetrical with respect to the nozzle system 6, so that the supply fluid l5 flowing through the connection 16 passes through the throttles 8 and the main nozzle 7 and interaction region 5 and is attached to the wall 12, to provide an output signal 14. The main jet may be deflected from the wall 12 to the wall 11 by means of partial jets issuing from the jet nozzles la, lb or 1c, and thus by the current formed in the mixing region 4a. As a result, upon such deflection of the main jet, the jet will become attached to the wall II and produce an output signal 13.

As illustrated in FIG. I, the axes of the jet nozzles 1a and 1c are directed at an obtuse angle a with respect to the baffle 3a, and the nozzle outlets of these jet nozzles are along a line that is at an acute angle [3 to the baffle 3a. In other words and as employed hereinafter, the angle a refers to the angle toward the mixing region between the axis of a jet nozzle and the baffle in the path of the jet nozzle, while the angle 8 refers to the mixing chamber between the baffle in the path of the jet from the nozzle and the line joining the two sides of the jet nozzle. Thus, in the arrangement of FIG. I, the nozzle outlets of the jet nozzles la to lo are arranged in a line or plane with the same angle B. The baffle 3a and the mixing region 4a are arranged so that the partial jets issuing from the jet nozzles la to 1c are aligned to deflect the main jet of the wall attachment device in a favorable manner, i.e., with as little power as possible in the partial jets. In this arrangement, the individual signal inputs 2a to 2c are decoupled.

In the arrangement of FIG. I, it is further to be noted that there are no adverse reactions either on the jet nozzles 1a to la, and hence on the input signals 2, in the event of return flows of fluid along the baffle 3a, since any such return flow bypasses the nozzles la through 1c and passes through suitable apertures 17 between the jet nozzles and the baffle 30 on the one hand, and between the nozzles and the nozzle system 6 on the other hand. In addition, there are no mutual return flows of fluid in the individual jet nozzles la to lc, so that the input signals 2a 2c are decoupled.

Referring now to FIG. 3, therein is illustrated a wall attachment device similar to that of FIG. 1, but in which a different form of multiple input jet element is provided to control the main jet. In this arrangement, the multiple input jet element is comprised of two nozzle systems 27. Each of the nozzle systems 27 has a main nozzle 28, the nozzles 28 being arranged, as in the arrangement of FIG. I, with their axes defining an obtuse angle with respect to the baffle 3a and the ends of the nozzles forming an actue angle with respect to the baffle 3a. The nozzles 28 may be in the form of Borda mouthpieces as illustrated. The nozzle systems 27 are separated from the nozzle systems 6 in baffle 3a to provide the aperture 17, as in the arrangement of FIG. 1.

Each of the nozzle systems 27 is in the form of a chamber having a pair of throttles 29 aligned with and separated from their respective nozzles 28. Input signals 2d to 21' are applied to the nozzle systems 27 so that, in each nozzle system, a separate input system is applied in the region between the respective nozzle and the first throttle, another separate input is provided between each pair of throttles, and a third input is provided in back of the throttle furthest from the respective nozzle. In this arrangement, only one of the input signals in each nozzle system 27 arrives in each intermediate chamber 21 between the respective nozzle 28 and the closest throttle 29 thereto. The nozzle systems 27 in this arrangement insure substantially equal volumes of fluid flow even though the input signals 2d to 21 have different potentials, where P is greater than Pzd.

FIG. 4 illustrates a fluidic device for obtaining complicated logical functions, the increased number of jet inputs provided being connected to minimize the space required for the device, and for providing parallel and series arrangements of the inputs. In this arrangement, the input signals 2k to 2m are applied to the jet nozzles 1d to If respectively the jet nozzles being positioned to direct their respective jets on the baffle 3b. As in the previous embodiments of the invention, the partial jets are directed into the mixing region 4b at an obtuse angle a with respect to the baffle'3b, and the fronts of the jet nozzles id to 1f form an acute angle B with re spect to the baffle 3b. The mixing region 4b is defined by the baffle 3b and a short wall or strap 22 parallel with and spaced from the baffle 3b. Fluid from the mixing region 4b, which now acts as a jet nozzle, flows to a curved baffle 3c, and thence into a mixing region 40. The output signal 23 of the device is formed from the mixing 4c.

The arrangement of FIG. 4 includes a second nozzle system including jet nozzles lg and 1h to which input signals 2n and are applied respectively. The nozzles lg and 1h direct their respective jets into the mixing region 4d and their obtuse angle with respect to the baffle 311. In order to save space, the baffle 3d is formed by the opposite side of the baffle wall 3b against which the outputs of jet nozzles 1d lf are directed. The plane joining the ends of the nozzles lg and 1h form an acute angle with respect to the baffle 3d as in the previously discussed arrangements. The mixing region 4d is defined by the baffle 3d and a short wall or strap parallel to and spaced therefrom. The fluid from the mixing region 4d, which now acts as a nozzle, is directed to the baffle 3c, and thence to the mixing region 4c. In addition, a further nozzle system including jet nozzles 1i and 1k is positioned to direct jets to the wall 30 at an obtuse angle with respect thereto, the plane defined by the ends of the nozzles 1i and 1k being at an acute angle 9 with respect to the wall 30. The signal inputs 2p and 2q are thus directed by their respective nozzles 1i and 1k respectively to the mixing region 40. The output signal 23 is thus formed from the combination of the signals 2k X 2q. The parallel end series interconnection of the several multiple input jet elements of FIG. 4 can also be considered to be a multiple input jet device having several groups of jet nozzles.

The mixing region 4c is defined by the baffle 3c and a short wall or strap 31 parallel thereto and spaced therefrom.

FIG. 5 illustrates a further embodiment of the invention, arranged in a fluidic circuit device having opposed interconnection of a pair of multiple input jet elements for the processing of signals, and also for the realization of complicated logical functions. In this arrangement, baffles 3e and 3f, which form the baffles for a pair of multiple input jet elements, are disposed at an angle of with respect to each other, and are separated by a duct 25 extending transversely therethrough. One of the multiple jet elements is comprised of the jet nozzles 1n and 10, to which the input signals Zr and 2s are applied, this element directing the jets toward the baffle Be. The other multiple input jet element is comprised of jet nozzles 11 and 1m arranged to receive the signal inputs 2! and 214 respectively and direct the jets toward the baffle 3f. As in the previous embodiments of the invention, the axes of the nozzles of the nozzle systems are directed at an obtuse angle with respect to their respective baffles, and the lines or planes joining the ends of the nozzles are at acute angles with respect to the their respective baffles. The outputs of the nozzles 1n and 10 are directed to the mixing region 4e, and the outputs of the nozzles II and 1m are directed to the mixing region 4f. Apertures 17 are provided at each side of each of the nozzle systems in order to prevent reactions from the jets directed toward each other in the mixing regions 42 and 4f on the input signals 2r to 2u The mixing regions 4e and 4f terminate in the interaction region 24 having the duct 25, as above noted, and an oppositely extending duct 26. If an input signal 2v is applied to the duct 26, an output signal 27 is formed in the duct 25 dependent upon the currents in the mixing regions 4e and 4f. In the absence of an input signal 2v however, the output signal 27, which now issues at the same time from the ducts 25 and 26, is composed merely of the currents of the mixing regions 42 and 4f.

The invention has been disclosed and described with reference to only several embodiments thereof, it will be obvious that many modifications and variations may be made without departing from the spirit or scope thereof, and is therefor intended in the following claims to cover all such variations and modifications.

What is claimed is:

l. A multiple signal input system for a fluidic circuit, said system comprising a baffle, wall means positioned with respect to a side of said baffle whereby the combination thereof forms a mixing region, a plurality of signal input nozzles each positioned to direct signal input jets toward the plane of the baffle whereby the angle between the axis of said jets and the plane of the baffle and which includes said mixing region is obtuse, said nozzles being arranged with their outlets in a plane which intersects the plane of said baffle at an angle that is acute on the side thereof towards said mixing region, a main nozzle for directing a main jet in said system for influence by fluid flow in said mixing region, said main nozzle being positioned for influence by said fluid flow only after input jet signals have interacted in said mixing region and means for deriving output signals from said main jet after influence thereof by fluid flow in said mixing region.

2. The multiple signal input system of claim 1 wherein the components of said system are arranged for substantially planar flow of fluids therethrough.

3. The multiple signal input system of claim 1 wherein said wall means which in part defines said mixing region is provided at a point spaced from said baffle beyond the points on said baffle where jets issuing from said nozzles impinge on said baffle.

4. The multiple signal input system of claim I for use in a wall attachment device of the type including a main nozzle, wherein said wall means comprises a wall of said main nozzle.

5. The multiple signal input-system of claim 1 further comprising a plurality of signal input sources for each of said nozzles, a plurality of throttles arranged in cascade in front of each of said nozzles and defining intermediate chambers between the throttles and between one of said throttles and its respective nozzle, and means for applying said signal inputs separately to said intermediate chambers.

.6. The multiple signal input system of claim 1 comprising a ground plate and a cover plate parallel thereto and spaced therefrom, and wherein said baffle, wall means and signal input nozzles are comprised of walls extending between said ground plate and cover plate.

7. The multiple signal input system of claim I further comprising second wall means positioned with respect to the other side of said baffle whereby the combination thereof forms a second mixing region, and a plurality of second input nozzles each positioned to direct signal input jets toward the plane of said bafile whereby the angle between the axis of said second input nozzles and the plane of said baffle and which include said second mixing region is obtuse, said second nozzles being arranged with their outlets in a plane which intersect the plane of said baffle at an angle that is acute on the side thereof toward said second mixing region.

8. The multiple signal input system of claim 7 further comprising a second baffle spaced from said first mentioned and second mixing regions, third wall means positioned with respect to said second baffle whereby the combination thereof forms a third mixing region, said first mentioned and second mixing regions forming jet nozzles having axes at an obtuse angle with respect to said second baffle in the direction toward said third mixing region and having ends defining a plane intersecting said second baffle at an acute angle toward said third mixing region.

9. The multiple signal input system of claim 1 comprising a second baffle positioned in a relationship with respect to said first mentioned baffle, duct means extending transversely of said first mentioned and second baffle at the adjacent ends thereof, second wall means positioned with respect to a side of said second baffle whereby the combination thereof forms a second mixing region, and a plurality ofv second signal input nozzles each positioned to direct signal input jets toward the plane of said second baffle whereby the angle between the axis of vsaid second nozzles and the plane of said second baffle and which includes said second mixing region is obtuse, said second nozzles being arranged with their outlets in,a plane which intersects the plane of said second baffle at an angle that is acute on the side thereof toward said second mixing region, whereby said first mentioned and second mixing regions are counter-connected.

10. A multiple signal input system for a fluidic circuit, said system comprising a baffle, wall means positioned with respect to a side of said baffle whereby the combination thereof forms a mixing region, and a plurality of signal input nozzles each positioned to direct signal input jets toward said baffle, said nozzles being positioned whereby the line of the baffle, a line joining the ends of all of the nozzles, and each jet axis define triangles of which the angles adjacent the line of the baffle surface are acute, said nozzles being positioned to direct jets toward said mixing region, a main nozzle for directing a main jet in said system for influence by fluid flow in said mixing region, said main nozzle being positioned for influence by said fluid flow only after input jets have interacted in said region, and means for deriving output signals from said main jet after influence thereof by said fluid flow in said region. 

1. A multiple signal input system for a fluidic circuit, said system comprising a baffle, wall means positioned with respect to a side of said baffle whereby the combination thereof forms a mixing region, a plurality of signal input nozzles each positioned to direct signal input jets toward the plane of the baffle whereby the angle between the axis of said jets and the plane of the baffle and which includes said mixing region is obtuse, said nozzles being arranged with their outlets in a plane which intersects the plane of said baffle at an angle that is acute on the side thereof towards said mixing region, a main nozzle for directing a main jet in said system for influence by fluid flow in said mixing region, said main nozzle being positioned for influence by said fluid flow only after input jet signals have interacted in said mixing region and means for deriving output signals from said main jet after influence thereof by fluid flow in said mixing region.
 2. The multiple signal input system of claim 1 wherein the components of said system are arranged for substantially planar flow of fluids therethrough.
 3. The multiple signal input system of claim 1 wherein said wall means which in part defines said mixing region is provided at a point spaced from said baffle beyond the points on said baffle where jets issuing from said nozzles impinge on said baffle.
 4. The multiple signal input system of claim 1 for use in a wall attachment device of the type including a main nozzle, wherein said wall means comprises a wall of said main nozzle.
 5. The multiple signal input system of claim 1 further comprising a plurality of signal input sources for each of said nozzles, a plurality of throttles arranged in cascade in front of each of said nozzles and defining intermediate chambers between the throttles and between one of said throttles and its respective nozzle, and means for applying said signal inputs separately to said intermediate chambers.
 6. The multiple signal input system of claim 1 comprising a ground plate and a cover plate parallel thereto and spaced therefrom, and wherein said baffle, wall means and signal input nozzles are comprised of walls extending between said ground plate and cover plate.
 7. The multiple signal input system of claim 1 further comprising second wall means positioned with respect to the other side of said baffle whereby the combination thereof forms a second mixing region, and a plurality of second input nozzles each positioned to direct signal input jets toward the plane of said baffle whereby the angle between the axis of said second input nozzles and the plane of said baffle and which include said second mixing region is obtuse, said second nozzles being arranged with their outlets in a plane which intersect the plane of said baffle at an angle that is acute on the side thereof toward said second mixing region.
 8. The multiple signal input system of claim 7 further comprising a second baffle spaced from said first mentioned and second mixing regions, third wall means positioned with respect to said second baffle whereby the combination thereof forms a third mixing region, said first mentioned and second mixing regions forming jet nozzles having axes at an obtuse angle with respect to said second baffle in the direction toward said third mixing region and having ends defining a plane intersecting said second baffle at an acute angle toward said third mixing region.
 9. The multiple signal input system of claim 1 comprising a second baffle positioned in a 180* relationship with respect to said first mentioned baffle, duct means extending transversely of said first mentioned and second baffle at the adjacent ends thereof, second wall means positioned with respect to a side of said second baffle whereby the combination thereof forms a second mixing region, and a plurality of second signal input nozzles each positioned to direct signal input jets toward the plane of said second baffle whereby the angle between the axis of said second nozzles and the plane of said second baffle and which includes said second mixing region is obtuse, said second nozzles being arranged with their outlets in a plane which intersects the plane of said second baffle at an angle that is acute on the side thereof toward said second mixing region, whereby said first mentioned and second mixing regions are counter-connected.
 10. A multiple signal input system for a fluidic circuit, said system comprising a baffle, wall means positioned with respect to a side of said baffle whereby the combination thereof forms a mixing region, and a plurality of signal input nozzles each positioned to direct signal input jets toward said baffle, said nozzles being positioned whereby the line of the baffle, a line joining the ends of all of the nozzles, and each jet axis define triangles of which the angles adjacent the line of the baffle surface are acute, said nozzles being positioned to direct jets toward said mixing region, a main nozzle for directing a main jet in said system for influence by fluid flow in said mixing region, said main nozzle being positioned for influence by said fluid flow only after input jets have interacted in said region, and means for deriving output signals from said main jet after influence thereof by said fluid flow in said region. 